Engine injection pump operating all cylinders or less

ABSTRACT

Multi-cylinder engine, and injection pump for operating same on a fraction of the number of cylinders, then a greater fraction of that number and, finally, all of the cylinders when operating in all higher portions of the speed range. Viewed the other way, the pump operates all cylinders at full load, and cuts a plurality or pluralities of those cylinders out of operation until, at engine idle, the transition is made such that only a plurality of cylinders is still firing, and all such transition control is consolidated in a controlled fuel metering sleeve in the pump. The pump is of the rotary distributor type, and has a variable volume pump chamber portion whereof the pump chamber number is materially fewer than the number of engine cylinders and preferably is limited to one or two pump chambers.

United States Patent [191 Gaines Aug. 14, 1973 [75] Inventor: John W.Gaines, Wheaton, 111.

[73] Assignee: International Harvester Company,

Chicago, Ill.

[22] Filed: Aug. 9, 1971 [21] Appl. No.: 170,178

[52] U.S. CI. 123/139 R, 123/139 AL, 417/294,

417/462 [51] Int. Cl.. F04b 49/08, F04d 15/00, F02m 39/00 [58] Field ofSearch 123/139 R, 139 AB,

123/139 AR, 139 AD, 139 AL, 139 AP, 140 R, 198 F; 417/302, 462

2,771,867 11/1956 Peras 123/198 F Primary Examiner-Laurence M. GoodridgeAttorney-Floyd B. Harman [57] ABSTRACT Multi-cylinder engine, andinjection pump for operating same on a fraction of the number ofcylinders, then a greater fraction of that number and, finally, all ofthe cylinders when operating in all higher portions of the speed range.Viewed the other way, the pump operates all cylinders at full load, andcuts a plurality or pluralities of those cylinders out of operationuntil, at engine idle, the transition is made such that only a pluralityof cylinders is still firing, and all such transition control isconsolidated in a controlled fuel metering sleeve in the pump. The pumpis of the rotary distributor type, and has a variable volume pumpchamber portion whereof the pump chamber number is materially fewer thanthe number of engine cylinders and preferably is limited to one or twopump chambers.

2 Claims, 9 Drawing Figures FINAL 171757? Pmmmws 3.152.138

SHEET 2 OF 5 JfiI/n 5071' John Z0. Gain 05 PAIENTEU i B55 rua IMkokhvWtR in wk whbk SHUT Off GOVERNOR 51 f f V Act VENT INCHES 1 25 2man/f9 Ina/vim 5/107 OFF 67/07 OFF Gal [EH09 -51 [EVE DISPlAtf/VEWT"VA/C1955 lfinfen for; (foil n l. (iaz'nes ENGINE INJECTION PUMPOPERATING ALL CYLINDERS OR LESS This application relates generally todiesel engine fuel control. It especially relates to means for improvingthe idle speed operation of a multi-cylinder high speed low inertiacompact diesel engine, with particular regard to steady speed controland low emissivity in the engine exhaust.

In a multi-cylinder engine, the cutting in and cutting out of operationof a plurality or pluralities of the cylinders enables such cylinders toburn fuel when needed, but not otherwise. The balance of the cylindersare needed as full time cylinders and are kept firing, thus maintaininghigh operating temperatures in the combustion chambers at all times. Thenon-firing plurality or pluralities are cut in and cut out of operationin an initial transition necessarily made with dispatch, withpunctuality, and with exactitude, and yet without abruptness. The lackof abruptness has been found to be critical in nature, and thecriticality makes it a problem.

In any case, diesel engines are generally sensitive and some dieselengines are particularly sensitive to surface operating temperatures ofthe exposed faces in the combustion chamber. Thermal efficiency isadversely effected when, during light load or engine idling, a criticalpart or parts of the combustion chamber are allowed to run comparativelycool to their normally hot operating temperature (500F. or more).

Obviously, eight cylinders can be operated, with fuel withheld at timesfrom some and supplied full time to others, simply by providing eightindividual fuel metering pumps in the pumping means. So a plurality, orset, of one or more cylinders can receive a metered amount, per stroke,of fuel differing from the amount received by another plurality or byother pluralities of the remaining cylinders.

But providing a number of differing, precision made pumps individual tocylinders of that same number makes for difficulty, if for no otherreason than unnecessarily multiplying expensive precision parts to bemade, and thereafter to be kept sorted so the similar but differing onesof the components are installed always in the critical places intendedfor, and suited to, each one. The measure of preciseness I am talkingabout necessitates either the lapping of the mating pumping surfaces, orelse the specially grinding and then the select-fitting up of the matingpumping parts, after grinding same to required tolerances measured inthe millionths of an inch.

In practice, matching a number of pumps to do identical metering forthat number of engine cylinders is a problem, at any time severaldifferent portions in a speed range are involved. And so, a furtherproblem arises by then deliberately unmatching the identical metering ofthe pumps to provide for such transient things as zero mm /strokemetering at times, or some initial transition flow in mm /strokemetering. Also, achieving the initial transition of fuel meteringwithout abruptness and with a plurality of transition cylinders matchedin metered fuel flow at the same time is also a problem.

On the other hand, the failure to cut out operation of some cylindersfor reduced engine load would introduce the greater problem of havingall cylinders firing on such small quantities of fuel that thecombustion chamber temperatures would run low, and under the attendantcondition of very low air swirl contributing to unreliable combustionand high emissivity in the exhaust.

My invention, of a controlled fuel metering sleeve in which transitioncontrol is consolidated for all cutting in and cutting out of cylinders,materially reduces or substantially eliminates the foregoing problems,as will now be explained. Benefits include smoother operation, lowerpump cost, clearer exhaust, hotter combustion and hotter combustionchambers, higher efficiency, and reduced engine surging in the low speedrange, particularly at or near idle.

In the drawings:

FIG. 1 is a longitudinal elevational view, in section, of a portmetering, opposed plunger, rotary distributor, diesel fuel injectionpump embodying the present invention;

FIG. 2 is the same as FIG. 1, but with only the control sleeves andassociated parts shown, and with the sleeves repositioned to shut off;

FIGS. 3 and 4 show the metering control sleeve as viewed from the leftrear and from the rear, respectively;

FIG. 5 is a developed sectional view taken along the lines VV of FIG. 4,as if the bore lands and grooves of the metering sleeve wereunwrapped-out flat;

FIG. 6 is a sectional view taken diagonally of the sleeve bore, alongthe section lines VIVI of FIG. 5;

FIG. 7 is a graph of flow-displacement curves resulting from four plusfour cylinder operation produced by four plus four sleeve structure inFIG. 5;

FIG. 8 corresponds to FIG. 5, and results in two plus two plus fourcylinder operation produced by the structure of FIG. 8; and

FIG. 9 is the same as FIG. 7, but shows one plus one plus two plus fourcylinder operation produced by a modified governor sleeve, not shown.

More particularly in FIG. I of the drawings, the housing or casing 10for the fuel metering pump device shown has three bolted togethersections consisting of a main housing 12 at one end, a primary pumphousing 14 at the opposite end, and a so-called distributor head housing16 assembled between the end sections or housings. An engine connectedpump shaft 18 extends longitudinally through the device and is journaledfor rotation in spaced apart roller and sleeve bearings 20 and 22,respectively, fixed in the main housing 12 and in the distributor headhousing 16.

The shaft I8 is the heart of the mechanism of several operatingcomponents within the housing 10, all contributing in properly timedrelation to supply metered amounts of fuel to the individual nozzles 23which communicate with combustion chambers in cylinders of that numberwithin an engine 24.

The shaft 18 is connected in the pump input drive 27, and a gearcoupling not shown directly couples together the crankshaft of theengine 24 and the pump input drive 27. The pump shaft 18 has alongitudinally drilled passage 25 which is intersected at one end by afirst transverse passage terminating in a metering port 26, andintersected at an intermediate point by a second transverse passageterminating in a timing port 28.

A centrally located charging pump component within the so-calleddistributor head housing 16 is shown having a diametric bore, andfurther having a cylindrical axial passage forming a pump chamber 30interposed in the passage and communicating with and inter sected by theinner ends of the diametric bore.

A distributor component comprises a retraction or delivery valve 32connected in the longitudinal passage 25 beyond the chamber so as tounseat or open in a direction away from the pump component. Thedistributor component further comprises a set of suction ports 34 whichintersect the passage 25 on the pump chamber side of the valve 32 andwhich periodically communicate with an annular chamber 36 which holdsthe so-called transfer fuel in the housing 16. The distributor componentfurther comprises a distributor port 38 which communicates with thepassage 25 on the opposite side of the delivery valve 32 and whichregisters at uniformly spaced apart intervals with each of a set ofhousing passages 40, and a set of fuel delivery lines 42 leading to theindividual nozzles 23. Socalled banjo fittings 44 connect the linesliquidtight to the distributor head housing 16, being secured to thelatter by individual hollow connecting screws 46.

A dual control sleeve component times pressure pulses for the actuationof the retraction valve 32. The dual sleeve component comprises a timingsleeve 48, and another sleeve 50, variously referred to herein andelsewhere as a control sleeve, a governor sleeve, and a metering sleevedepending upon the functional relationship specifically referred to. Thetiming sleeve 48 rotatably receives the pump shaft 18 on a proximalportion relative to the pump chamber 30, and the metering sleeve 50rotatably receives the shaft 18 on a distal portion between a governorcomponent 52 and the timing sleeve 48. An alignment pin 54 connectedbetween the sleeves 48 and 50 holds them so as to be non-rotatable butrelatively axially movable to one another. The timing sleeve 48 has aconnection, not shown, to a pivoted arm termed a governor spring arm 56.

Straight milled slots 58, corresponding in number to the cylinders ofthe engine 24 and located in the bore of the timing sleeve 48, areparallel to the pump shaft axis and cooperate with the timing port 28 tospill fuel therefrom during short, equally spaced apart intervals.Milled right-hand helix spill grooves 60, corresponding in number to thecylinders in the engine 24 and formed in the bore of the metering sleeve50, cooperate with the metering port 26 to control injection duration byallowing fuel to escape therefrom during short, equally spaced apartintervals in the cycles. The straight timing sleeve slots 58 keep thebeginning of delivery constant whereas the milled right-hand helix spillgrooves 60, when the metering sleeve 50 is adjusted by the governorcomponent 52, perform their metering function by varying the end of fueldelivery. Operation of the governor component against a concavo-conicalcup surface of the metering sleeve 50 is believed obvious, and in anycase, that component 52 is already detailed in another specificationowned by the same assignee, U.S. Pat. No. 3,311,100.

The charging pump component referred to provides the pressure for thetimed pressure pulses closing and opening the delivery valve 32, andincludes two rotary and reciprocatory pump plungers 62 mounted inopposite ends of the diametric bore so as to form two opposed pumpchambers or, viewed another way, two opposite movable wall portions ofone chamber 30. The charging pump component further includes a cam ring64 fixed in the housing 16 in the plane of the pump plungers 62, a pairof rotary and reciprocatory cam followers or rollers 66 which ride alonginwardly protruding cams on the ring 64, and an interposed tappet 68connecting each roller to a different one of the plungers 62 causing theplungers to periodically foreshorten and re-expand a precompressed,interposed return spring 70 during pumping. The cams on the ring 64correspond in number to the cylinders of the engine 24.

Further components in the device, indicated by general referencenumerals, are a control component 72, a maximum torque component 74, atiming plate component 76, and a transfer or primary pump component 78.

PUMPING FIG. 1

When the device is pumping, diesel fuel from a tank 80, which fuel isultimately drawn into the pump chamber 30, flows in a path leadingthrough a fuel tank outlet conduit 82, a transfer intake port 84 whichis in the housing 14 and which communicates with the suction side of thepump mechanism of the primary pump 78, a transfer outlet port 86 whichcommunicates with the pressure side of the pump 78, a transfer conduit88 leading from the outlet port 86 and including therein a final filter90, the annular chamber 36, a communica tion charging passage 92 in thehousing 16 which is connected during shaft rotation to the suction ports34 in periodically timed relation, and a set of diagonal intake passages94 formed in the shaft 18, and thence into the pump chamber 30.

The pump plungers 62 collapse radially toward one another on thedischarge stroke of the pump, and the fuel follows a sequence flowing indifferent directions through a three-way split path. Duringpredetermined initial movement of collapse of the plungers 62, fuelescapes from the shaft 18 into the pump housing 12 through theregistering straight timing slot 58 until spilling of the fuel is cutoff by the timing sleeve 48 covering the timing port 28. During furthercollapsing movement of the plungers 62, fuel pressure increases so as tounseat and open the retraction valve 32, and fuel through the unseatedvalve 32 is forced through the registering one of the fuel nozzledelivery lines 42. During final, radially inward collapsing movement ofthe plungers 62, a milled right-hand helical spill groove 60 registerswith the metering port 26 so as to-terminate the duration of injectionby spilling the balance of the pumped fluid into the main housing 12.

A drain conduit 96 returns a portion of the spilled fuel from the mainhousing 12 of the device to the fuel tank 80. A spring-loadedrecirculation valve, not shown, connected between the housing 12 and thesuction side of the primary pump component 78 returns another portion ofthe spilled fuel. Finally, a pressure regulating valve 98 connectedbetween the annular chamber 36 and the suction side of the primary pumpcomponent 78 unseats and returns fuel to the latter whenever pressurebecomes excessive on the pressure side of the pump component 78.

The delivery valve 32 functions to maintain residual pressure in eachdelivery line 42 after each injection takes place, doing so at that timeby slightly enlarging the volume of the line in well known way as thevalve retracts and reseats.

SHUTOFF FIG. 2

The dual control sleeve component is concentric to the pump shaft 18,which supports the metering sleeve 50 to turn and slide on its axis 100and also supports the timing sleeve 48 to turn and slide on its axis102, the axes 100 and 102 being coaxial.

For purposes of oversimplifying and yet making more graphic hereinafterthe function of the metering sleeve 50, the shutoff position of FIG. 2shows both sleeves moved manually fullback on the shaft 18 exposing themetering port 26 and the timing port 28. Shutoff makes it clearlyimpossible to trap fuel in the shaft 18, because of zero duration ofinjection and because the start of injection is never timed for.Consequently, the plunger action cannot pressurize and deliver fuel tothe cylinders, regardless of shaft rotation.

In practice, however, the excessive amount of sliding travel required bythe metering sleeve 50 for shutoff is not only unnecessary butundesirable. A manual shutoff lever 104 is simply provided so as toengage the arm 56 and slide only the timing'sleeve 48 to the fullbackposition for shutoff, as shown in FIG. 2. Shutoff is just as absolute,in result.

FIRING ORDER ALL CYLINDERS ACTIVE A diesel engine is used in examples ofmy invention now to be given, the engine and examples being by way ofillustration and not of limitation. Such engine, in one preferredembodiment, is a 90 V8 solid injection engine having, from front torear, the cylinder numbering l, 3, 5, 7 in the left bank and 2, 4, 6, 8in the right bank. The firing order is a common one, for example, 2 l 87 3 6 5 4 2 etc., wherein I treat cylinder No. 2 as the firing cylinderin all cases except during engine shutoff as described in connectionwith FIG. 2.

The injection, ignition, and attainment of peak combustion pressuretranspire rapidly in any cylinder firing, all occurring in the course ofa total, for example, of 22 of crankshaft rotation.

The engine for these illustrative purposes has a compact low inertiadesign, is capable of operation over a wide range of speeds and loadswherein the no-load idle speed may be on the order of one-eighth themaximum speed, and has direct injection. A four-stroke cycle is employedand, for that reason, the gear coupling referred to interposes a [:2gear reduction between the driving crankshaft of the engine and the pumpinput drive 27. Thus, in properly timed relation to crankshaft rotation,the present device is operable to pump one metered quantity of fuel toeach cylinder during every two revolutions of the crankshaft.

4 PLUS 4 CYLINDER EXAMPLE FIGS. 3, 4, 5, 6,

In these figures, the mechanical function of the metering port 26 is tofollow counterclockwise motion relative to the metering sleeve bore asviewed in FIGS. 3 and 4, and top-to-bottom motion relative to the boreof the sleeve 50 in FIG. 5. The hydraulic function of metering port 26in FIG. 5 is to have relative left to right axial motion to the sleevebore in an initial manner so as to be covered, and in a continuingmanner to increase duration of injection and hence pump more fuel to theengine. The hydraulic function of the designated governor or meteringsleeve 50 in its motion relative to the metering port 26 is axially leftto right in FIG. 7 initially to cover the metering port and subsequentlyto increase duration of injection and hence to pump more fuel to theengine cylinders.

With particular reference to FIG. 3, the right-hand helix spill groovesare identified there and elsewhere by their general reference numeral60, whereas individual identifying numerals 60a, 60b, 60c, 60d, and 602used in FIGS. 4, 5, and 6 distinguish the grooves sequentially in theiroperation order.

Viewed mechanically, the difference in FIG. 5 be tween the metering portwhen in the position shown by the solid line 26 for following anindicated four cyls. idle circular path about the bore, and the meteringport when in the broken line position for following the indicated fullpower circular path about the bore of the sleeve is that four cylindersare joined by four more active cylinders only when needed, and otherwisethey are not joined by the latter four cylinders. In the full power pathjust referred to, the metering port 26 encounters a succession ofcontrol edges 106 of the spill grooves all inclined at the same singleangle to the sleeve bore axis, not shown. In terms of the direction ofadvance of the port 26, the port has a late opening intersection in thelate opening full power path and the significance is that the injectionduration is delayed in its termination to provide maximum fuel flow atfull load.

In contrast to alternating ones of the control edges which are milleduniformly from end-to-end with the single angle as shown at 106, eachremaining one of the control edges provided on the spill grooves has adouble angle control edge where the second angle edge is shown at 108.Thus, each remaining one of the control edges has for a major part oneangle which ultimately diverges into a greater angle 108 to the sleevebore axis, not shown, so that the corresponding four cylinders willreceive no fuel when the metering port has the relative mechanicalposition shown by full line 26 in the four cyls. idle path. And yet themetering sleeve in the idle position as set by the governor causes thefour cylinders firing at idle to receive more fuel than they would in anengine in which all cylinders operate at idle.

Therefore the engine does not die and, with respect to the firingcylinder (reference cyl. 2, as the starting point), the 1st cylindernext in rotation (cyl. 1, FIG. 5) has the effective pump strokeprematurely shortened to the point of zero injection duration, and it isthe large angle edge 108 of groove 60b which causes it to be anon-firing cylinder. The second cylinder next in rotation (cyl. 8) is afiring cylinder, the third cylinder next in rotation is a non-firingcylinder, and so forth.

In FIG. 6, the greater angle edge 108 is cut in each remaining one ofthe spill slots by a rotary milling cutter, introduced in anintersecting left-hand helix path for a short distance at only one endof the control sleeve bore. The spill grooves 60 are otherwise all thesame within the bore.

The transition in the initial cutting in and cutting out of operation ofthe four cylinders 1, 4, 6, and 7 appears as a narrow crosshatched stripin FIGS. 5 and 7, and occupies a small portion of the speed range nearerthe idle end than the full power end of the range. Thus during engineslowdown for instance, the double angle control edges reduce fuel tocylinders l, 4, 6, and 7 at a greater rate than the remaining fourcylinders so that, at the time cylinders l, 4, 6, and 7 are completelycut out, the movement of the control sleeve is still within the controlrange of movement of the four spill grooves controlling those remainingfour cylinders.

Nevertheless, the difference in magnitude between the second anglecontrol edge 108 and the single angle control edge 106 is not enough tomake the angle 108 appreciably large. Hence, the transition isessentially a gradual one without such abruptness as to cause enginesurging or drastic fluctuations within the crosshatched strip of thespeed range. This graduality is visually borne out from the appearanceof the second angle as shown at 108 in FIG. and the diagonal portion ofthe flow-displacement curve as shown at 112 in FIG. 7 for cylinders l,4, 6, and 7. For contrast, use the angle 106 as the basis of comparisonin FIG. 5, and the portion 114 of the flow-displacement curve forcylinders 2, 3, 5, and 8 as the basis of comparison in FIG. 7.

For brevitys sake, illustrated portions of the entire developed view ofthe grooved sleeve bore 50 are omitted from FIG. 5 because they arebelieved self-evident and self'explanatory, and written portions of acomplete description of FIGS. 5 and 7 are omitted herefrom because theyare believed self-evident.

Four active cylinders are not essential for satisfactory idle and twoinitial transitions, which can optionally be contiguous as provided, cancut out two pluralities of the cylinders and leave only two cylindersfiring at idle. An example follows. I

2 PLUS 2 PLUS 4 CYLS. EXAMPLE FIG. 8

A grooved bore for the control sleeve 250 shown in this figure providestwo contiguous narrow crosshatched paths encountered by the meteringport, not shown, during engine slowdown. The groove 260a (as well as260a) passed over by the metering port has only a first control angleedge 206, which is a single angle edge. A second control angle edge 208in groove 2600 for the second cylinder next in rotation (cyl. 8, andalso cyl. 5) causes the cylinder concerned to cut out of operationimmediately before the engine reaches idle (engine idles on cyls. 2 and3).

Theretofore, second and third control angle edges 209 and 210 in spillgrooves 260b and 260d will have caused the first and third cylindersnext in rotation (cyls. l and 7, and also 6 and 4) to have cut out ofoperation. The angled edge 208 can be cut with a rotary milling cutterin a wide milling pass. Preferably however, the offset second and thedoubly offset third angled edges 209 and 210 are cut with a narrowerrotary milling cutter introduced in overlapping and successive millingpasses to minimize metal removal.

Two firing cylinders are not essential for satisfactory idle and severalinitial transitions, which can optionally be separated in speed, can cutout several pluralities of cylinders and the engine can have aone-cylinder idle. An example follows.

I PLUS 1 PLUS 2 PLUS 4 CYLS. EXAMPLE FIG.

In the initial transitions as the engine increases speed and power inthe curves of this figure, it can be seen that in the one-cylinder idleportion 318 of the flowdisplacement curve the engine will idle oncylinder 2 drawing slightly more than mm /stroke of the pump. That is tosay, the single cylinder (cyl. 2) will fire once for every twocrankshaft revolutions. In the narrow crosshatched strip of transitioncontaining the curve portion 316, cyl. 3 cuts into operation at a rateaccording to the portion 316 and at, for instance mm per stroke, each ofcyls. 2 and 3 is receiving approximately 25mm fuel flow and the twocylinders are matched and firing at equally spaced apart intervals.

A slight speed increase ensues, after which another crosshatchedtransition occurs, represented by the narrow strip containing theportion 3 of another flowdisplaeement curve. Cyls. 5 and 8 are thus cutinto operation at a rate according to the portion 314 and, at a fuelconsumption of approximately 30mm per stroke, the four cyls. 2, 3, 5,and 8 are actively firing and are each being supplied the same with 30mmof fuel per stroke.

After a slight further increase in engine speed, the final transitionrepresented by a crosshatched strip is encountered containing theportion 312 of the flowdisplacement curve for the remaining four cyls.l, 4, 6, and 7. At and above a fuel flow of, for instance 35mm per pumpstroke, the eight cylinders are balanced with each receiving 35mm ormore fuel per stroke of the pump.

The separation in speed between the several noncontiguous crosshatchedtransition strips is to provide further assurance against surging of theengine in the transitions. 1

For purposes of the example of FIG. 9, a single metering port such asthe metering port 26 of FIG. 2 is all that is provided for metering. Inother words, the only spill groove affording a finite duration ofinjection will be the late opening groove 60a which upon opening themetering port 26 perforce terminates injection with each firing of cyl.2 during idle. The remaining cylinders will all have zero duration ofinjection and be nonfiring cylinders during engine idle.

However, a second metering port 426 which must be diametric to the firstmetering port 26 (FIG. 2) can be provided in thepump shaft 18 of allother examples of the device herein given. Similarly, a second timingport 428 diametric to the timing port 28 can be provided, and the reasonis to meter more precisely with sharp cutoff of injection from thenozzles without dribble,

and equally sharp start of injection. Better control is known to beafforded on rate and quantity of fuel injected, when the nozzleoperation is attended by quick opening and quick closing nozzle valveaction.

In FIG. 2, devices made in production according to my invention can bemade all the same except for substitutable metering sleeves 50. Theengine in which such a device is installed will have either two cylinderidle or four cylinder idle. Such substitutable sleeves can furtherdiffer among themselves in the matter of where various pluralities ofcylinders are to be cut in and cut out of operation in the speed rangeand whether transitions will be made contiguously or separated slightlyfrom one another. Engine speed surges at the time, whether appreciableor barely perceptible, are nevertheless of no really objectionableamount.

If the devices in production are made with a single metering port 26,then the engine is afforded the fuller flexibility of a one cylinderidle, two cylinder idle, or four cylinder idle depending upon themetering sleeve 50 selected. The advantage is that only a singlesubstitutable part is employed.

The result is a net reduction in the amount of fuel supplied duringno-load idle operation compared to the prior art engines in whichmetering sleeves have hitherto caused them to idle on all cylinders.Moreover, the no-load idle in such prior art engines requires so littlefuel for each of the cylinders that consistent injection of equalquantities of fuel to each cylinder can be difficult, and inadequatemixing of the fuel with slow moving swirl air results in poor combustionand comparatively low combustion chamber temperature, with a tendencytoward erratic operation and excessive exhaust emissions.

Obviously, a multi-cylinder diesel engine which idles on one cylinderwill display the best idling performance when subjected to comparisonfor its high thermal efficiency and high level of combustion chambertemperature. And one-cylinder idling has manifest advantage in thematter of reduced emissions when an engine, so operating, is beingrapidly decelerated or is being motored by drive from the tractionwheels during sustained downhill coasting, for example.

Variations within the spirit and scope of the invention described areequally comprehended by'the foregoing description.

What is claimed is:

l. A fuel injection pump for an engine having a number of cylinders andintended to idle on fewer than all of the number, said pump having avariable volume pump chamber portion whereof the pump chamber number ismaterially fewer than the number of engine cylinders and wherein thepump input drive produces pump strokes variable in effectiveness, acontrolled sleeve having an individual spill duct for each of, andassociated with each of, the engine cylinders and formed with a controledge inclined with respect to the sleeve axis, a pump shaft connected inthe pump input drive, said pump shaft rotatably and slidably mountingsaid sleeve and presenting thereto a metering port in flow communicationwith the cylinders and with the variable volume pump chamber portion,the intersection of a control edge with the metering port determiningthe end of the effective pump stroke for each engine cylinder and thusthe amount of the metered fuel charge pumped thereto, engine means foroperating the pump shaft in timed relation to the operation of saidengine cylinders, and slide means to slide the controlled sleeve forchanging the control edge-metering port relationship and effective pumpstrokes of the pump chamber portion, said sleeve thus varying themetered charge to the individual cylinders, and having the control edgeinclinations arranged so that some have greater inclination than others,whereby the charge to some cylinders decreases in like amount amongthemselves, but at a greater amount than in the others.

2. A fuel injection pump for an engine having a number of cylinders andintended to idle on fewer than all of the number, said pump having avariable volume pump chamber portion whereof the pump chamber number ismaterially fewer than the number of engine cylinders and wherein thepump input drive produces pump strokes variable in effectiveness, acontrolled sleeve having an individual spill duct for each of, andassociated with each of, the engine cylinders and fonned with a controledge inclined with respect to the sleeve axis, a pump shaft connected inthe pump input drive, said pump shaft rotatably and slidably mountingsaid sleeve and presenting thereto a metering port in flow communicationwith the cylinders and with the variable volume pump chamber portion,the intersection of a control edge with the metering port determiningthe end of the effective pump stroke for each engine cylinder and thusthe amount of the metered fuel charge pumped thereto, engine means foroperating the pump shaft in timed relation to the operation of saidengine cylinders, and slide means to slide the controlled sleeve forchanging the control edge-metering port relationship and effective pumpstrokes of the pump chamber portion,'said sleeve thus varying themetered charge to the individual cylinders, and having the control edgeinclinations arranged so that a parallety have greater inclination thanothers, whereby the charge to a plurality of said cylinders decreases inlike amount among themselves, but at a greater amount than in theothers, some of the just said plurality of control edge inclinationsprovided by first, second, and third edges on each spill duct, arrangedoffset from one another.

t t t

1. A fuel injection pump for an engine having a number of cylinders andintended to idle on fewer than all of the number, said pump having avariable volume pump chamber portion whereof the pump chamber number ismaterially fewer than the number of engine cylinders and wherein thepump input drive produces pump strokes variable in effectiveness, acontrolled sleeve having an individual spill duct for each of, andassociated with each of, the engine cylinders and formed with a controledge inclined with respect to the sleeve axis, a pump shaft connected inthe pump input drive, said pump shaft rotatably and slidably mountingsaid sleeve and presenting thereto a metering port in flow communicationwith the cylinders and with the variable volume pump chamber portion,the intersection of a control edge with the metering port determiningthe end of the effective pump stroke for each engine cylinder and thusthe amount of the metered fuel charge pumped thereto, engine means foroperating the pump shaft in timed relation to the operation of saidengine cylinders, and slide means to slide the controlled sleeve forchanging the control edge-metering port relationship and effective pumpstrokes of the pump chamber portion, said sleeve thus varying themetered charge to the individual cylinders, and having the control edgeinclinations arranged so that some have greater inclination than others,whereby the charge to some cylinders decreases in like amount amongthemselves, but at a greater amount than in the others.
 2. A fuelinjection pump for an engine having a number of cylinders and intendedto idle on fewer than all of the number, said pump having a variablevolume pump chamber portion whereof the pump chamber number ismaterially fewer than the number of engine cylinders and wherein thepump input drive produces pump strokes variable in effectiveness, acontrolled sleeve having an individual spill duct for each of, andassociated with each of, the enGine cylinders and formed with a controledge inclined with respect to the sleeve axis, a pump shaft connected inthe pump input drive, said pump shaft rotatably and slidably mountingsaid sleeve and presenting thereto a metering port in flow communicationwith the cylinders and with the variable volume pump chamber portion,the intersection of a control edge with the metering port determiningthe end of the effective pump stroke for each engine cylinder and thusthe amount of the metered fuel charge pumped thereto, engine means foroperating the pump shaft in timed relation to the operation of saidengine cylinders, and slide means to slide the controlled sleeve forchanging the control edge-metering port relationship and effective pumpstrokes of the pump chamber portion, said sleeve thus varying themetered charge to the individual cylinders, and having the control edgeinclinations arranged so that a parallety have greater inclination thanothers, whereby the charge to a plurality of said cylinders decreases inlike amount among themselves, but at a greater amount than in theothers, some of the just said plurality of control edge inclinationsprovided by first, second, and third edges on each spill duct, arrangedoffset from one another.